excretion during 16 days accounted for approximately 50% of the drug. The fecal route of excretion did not seem to be important. Protriptyline has uniquely low dosing among TCAs, likely due to its exceptionally long terminal half-life. It is used in dosages of 15 to 40 mg/day, whereas most other TCAs are used at dosages of 75 to 300 mg/day. The maximum dose is 60 mg/day. Therapeutic levels of protriptyline are typically in the range of 70 to 250 ng/mL (266-950 nmol/L), which is similar to that of other TCAs Chemistry Protriptyline is a tricyclic compound, specifically a dibenzocycloheptadiene, and possesses three rings fused together with a side chain attached in its chemical structure. Other dibenzocycloheptadiene TCAs include amitriptyline, nortriptyline, and butriptyline. Protriptyline is a secondary amine TCA, with its N-methylated relative amitriptyline being a tertiary amine. Other secondary amine TCAs include desipramine and nortriptyline. The chemical name of protriptyline is 3-(5H-dibenzo[a,d][7]annulen-5-yl)-N-methylpropan-1-amine and its free base form has a chemical formula of C19H21N1 with a molecular weight of 263.377 g/mol. The drug is used commercially mostly as the hydrochloride salt; the free base form is not used. The CAS Registry Number of the free base is 438-60-8 and of the hydrochloride is 1225-55-4. History Protriptyline was developed by Merck. It was patented in 1962 and first appeared in the literature in 1964. The drug was first introduced for the treatment of depression in 1966. Society and culture Generic names Protriptyline is the English and French generic name of the drug and its , , and , while protriptyline hydrochloride is its , , and . Its generic name in Spanish and Italian and its are protriptylina, in German is protriptylin, and in Latin is protriptylinum. Brand names Protriptyline is or has been marketed throughout the world under a variety of brand names including Anelun, Concordin, Maximed, Triptil, and Vivactil. Availability The sale of protriptyline was discontinued in the United Kingdom, Australia, and Ireland in 2000. References Alpha-1 blockers Antihistamines Dibenzocycloheptenes Muscarinic antagonists Secondary amines Serotonin receptor antagonists Serotonin–norepinephrine reuptake inhibitors Tricyclic antidepressants